Keyless chain lock

ABSTRACT

A keyless chain lock providing a multiposition latching of a hinged door, the lock including an anchor plate secured to a door jamb, a flexible chain secured at one end to the anchor plate and fastened at the other free end to a chain knob, and a locking plate coupled to a spacer plate secured to the surface of a door, the locking plate having a main longitudinal slot directed generally away from said anchor plate with an enlarged opening at the distal end of the slot for insertion of the chain knob into the slot, and, having two radial side slots connected to the main slot into which said chain knob may be alternately tracked, thereby forming three alternate positions that the hinged door may be oriented, a substantially closed position when the chain knob is in the radial side slot most distant from the anchor plate, a partially opened or intermediate position when the chain knob is in the radial side slot closer to the anchor plate, and a substantially opened position when the chain knob is at the end of the main slot adjacent the anchor plate.

United States Patent [191 Scholtze Nov. 18, 1975 KEYLESS CHAIN LOCK [76]Inventor: Herman J. Scholtze, 1802 Sacramento St., Berkeley, Calif.94702 [22] Filed: Apr. 15, 1974 [21] App]. N0.: 461,248

[52] US. Cl. 292/264 [51] Int. Cl. E05C 17/36 [58] Field of Search292/264, 268

[5 6] References Cited UNITED STATES PATENTS 257,986 5/l882 Skerrett292/264 747,866 12/1903 Diehl 292/268 FOREIGN PATENTS OR APPLICATIONS68,300 4/1893 Germany 292/264 Primary Examiner-Robert L. Wolfe AssistantExaminerCarl F. Pietruszka Attorney, Agent, or FirmTheodore J. Bielen,Jr.

[ 5 7] ABSTRACT A keyless chain lock providing a multiposition latchingof a hinged door, the lock including an anchor plate secured to a doorjamb, a flexible chain secured at one end to the anchor plate andfastened at the other free end to a chain knob, and a locking platecoupled to a spacer plate secured to the surface of a door, the lockingplate having a main longitudinal slot directed generally away from saidanchor plate with an enlarged opening at the distal end of the slot forinsertion of the chain knob into the slot, and, having two radial sideslots connected to the main slot into which said chain knob may bealternately tracked, thereby forming three alternate positions that thehinged door may be oriented, a substantially closed position when thechain knob is in the radial side slot most distant from the anchorplate, a partially opened or intermediate position when the chain knobis in the radial side slot closer to the anchor plate, and asubstantially opened position when the chain knob is at the end of themain slot adjacent the anchor plate.

3 Claims, 5 Drawing Figures U.S. Patent Nov. 18, 1975 xsa FIG. .1.

1 FIG. 2

'2 FIG. 3

Ni I

KEYLESS CHAIN LOCK BACKGROUND OF THE INVENTION Keyless chain locks arecommonly used on doors in addition to other conventional key locks bothto provide an additional protection from unauthorized entry by a devicethat reduces tampering from the outside and to allow a party topartially open a door to receive small packages or identify callerswithout total loss of security. Conventional chain locks customarilyinclude an anchor plate on a door jamb with a chain attached at one endto the anchor plate. The free end of the chain is attached to a chainknob or stud that is inserted into the distal end of an elongated slotin a locking plate fixed to the open door. In such arrangements, thechain knob is positioned in the elongated slot closest to the anchorplate. In such single-position chain latches, a substantial slack isprovided in the chain. While this slack allows the door to be partiallyopened for the desirable purpose of receiving small packages or mail, ithas the undesirable aspect of being subjected to tampering.

For example, the knowledgeable burglar can easily eliminate aconventional cylinder key lock by drilling the cylinder or pulling thelocking mechanism. A door protected by the conventional chain lock canthen be partially opened exposing the chain. The chain can be quicklysevered by bolt cutters and entry gained.

While some prior art devices attempt to eliminate this effect byswinging multiposition shield plates which cooperate with the trackingslot in the locking plate, or tortuous tracking slots, these devices arecumbersome and difficult to operate, particularly in time of stress ornervousness. The keyless chain lock of the present invention eliminatesthe undesirable feature of the conventional locks by providing thelocking mechanism with an operating position in which the door cannoteven be partially opened and accomplishing this feature in a simple andefficient manner which has not been considered by prior devices.

SUMMARY OF THE INVENTION The keyless chain lock of this invention isconstructed to allow the user alternatives in its use and operation. Thechain lock has a uniquely arranged locking plate which allows the chainknob at the free end of the chain to be positioned in one of threepositions. A first closed position in which the chain is taut preventingany opening of the door. In this position, the user can rest assuredthat even if his additional key lock is picked or pulled, he will stillbe protected and the chain of his secondary chain lock will not beexposed and severed. A second intermediary position in which the chainis partially slack allows the door to be opened a crack. In thisposition, conversation can be engaged and identifications made withoutfear that a partial entry by arm or foot be attempted. A third part openposition in which the chain is in its greatest slack conditionapproximates the single position of the conventional chain lock. In thisposition, the door can be opened to a sufficient degree that smallpackages can be exchanged and a full view of a caller made.

It is clear that the two positions which will be most used are theclosed position and the part open position. For convenience ofoperation, the locking plate is specifically and uniquely designed toallow the chain knob to be moved from the closed position to the partopen position merely by a flip of the finger on the chain 2 knob. Suchaction permits the chain knob to self-track to the part open position.Where caution is the guide, the chain knob can alternately be releasedfrom the closed position and deliberately positioned in the intermediateposition.

The novel construction and arrangement of the keyless chain lock of thisinvention, which operates in this simple and convenient manner, isdescribed in greater detail in the following detailed description of thepreferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view,partially fragmented, of the keyless chain lock mounted on a door andassociated structure.

FIG. 2 is a cross-sectional view, partially in phantom, of thearrangement in FIG. 1, taken on the lines 2-2 in FIG. 1.

FIG. 3 is a cross-sectional view, partially fragmented, taken on thelines 33 in FIG. 1.

FIG. 4 is a front view detailing the locking plate in the keyless chainlock of FIG. 1.

FIG. 5 is a front view detailing the spacer plate which accompanies thelocking plate in the keyless chain lock of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1,the keyless chain lock designated generally by reference numeral 10 isillustrated mounted on a door 12 and accompanying door-jamb structure14. The chain lock 10 has an anchor plate 16 secured to the door-jambstructure 14 by two wood screws 18. The anchor plate 16 has an anchorbracket 20 fixed to the plate to which an end link 22 of a flexiblechain is attached. The flexible chain 24 has a stud or chain knob 26attached to the distal or free end link 28 of the chain 24. The anchorplate includes an aperture 30 into which the chain knob 26 may beinserted for retaining the flexible chain when the lock is not in use.

Attached to the door 12 is a locking plate 32 and a spacer plate 34, thelatter shown in phantom in FIG. 1 and visible in the cross-sectionalview of FIG. 2. The locking plate 32 and spacer plate 34 are fastened tothe door by a plurality of wood screws 36.

Additionally, a filler bracket 38 is attached to the door 12 adjacentthe anchor plate. While the filler bracket is not essential to aproperly installed chain lock, it is preferred for two important reason.First, the filler bracket protects the door from damage from theflexible chain during ordinary use. Second, and perhaps moreimportantly, the filler bracket provides for a final adjustment of thechain 24 when the chain is extended to the taut position shown inFIG. 1. After the locking plate 32 and spacer plate 34 are installed andthe chain 24 is arranged as shown in FIG. 1, the filler bracket 38 canbe installed to provide a taut condition to the chain. Adjustment can bemade by the installation of one or more shim plates 40 as shown in FIG.2. The filler bracket is secured to the door by wood screws 42 in thesame manner as the anchor plate 16.

As shown in FIGS. 1 and 4, the locking plate has a main slot 44 that islongitudinally arranged at an angle to the horizontal. While the anglemay be varied somewhat, the angle in the preferred embodiment isapproximately 20 which provides for an efficient operation of the chainlock as described hereafter. The end of the slot most distant from theanchor plate 16 has an enlarged aperture 46 allowing insertion of thechain knob 26 as described in greater detail below. Depending from themain slot 44 is a first radial side slot 48 and a second radial sideslot 50. The point from which the radii of these two side slots 48 and50 are constructed is at the end 52 of the main slot closest the anchorplate 16. In this manner, the flexible chain 24 being pivoted from theanchor bracket 20 on the anchor plate encounters a slight additionaldisplacement from its point of pivot, at the anchor bracket when thechain knob 26 is displaced into the side slots 48 and 50. Thisdisplacement is of particular importance when the chain knob isdisplaced into the first, more distant side slot 48. In this position,the chain knob encounters a slight wedging action by the additionaldisplacement, thereby providing a leverage to increase the tautness ofthe chain 24 when finally positioned as shown in FIG. 1. Thus, thedesired resultant tautness can be achieved without making it difficultto initially move the chain knob 26 to the first side slot 52 as wouldbe the case were the radius of the slot centered on a point at theanchor bracket 20 rather than the end 52 of the main slot 44.

Additionally, when the chain knob is released from the first side slot48 by a flip of the finger, the relief in tautness aids in carrying thechain knob up to the aperture 46 at the end of the main slot 44. At thispoint, the angle or slope in the main slot and the weight of the chainautomatically cause the chain knob 16 to track down to the end of theside slot bypassing the second side slot 50.

If placement of the chain knob 26 from the first slot 48 to the secondor intermediate side slot 50 is desired, the chain knob 26 is raisedfrom the first slot 48 in the same manner as above described, but mustbe deliberately carried to the second slot 50 and placed therein. Thisoperation is in keeping with the normal consciousness of an operatorwho, in the usual case, will want the chain lock operated from aposition where the door is closed to a position where it is most open.When the operator is cautious, he will naturally take care todeliberately place the chain knob in the intermediate position.

This intermediate position is shown in FIG. 2, where the chain knob 26is shown placed in the intermediate second side slot 50. In thisposition, the door 12 is only slightly open, thus allowing for onlypartial inspection of a caller or the receipt of only small or thinpackages. The closed position, where the chain knob 26a is positioned inthe distant first side slot 48a, as shown in FIG. 1, is illustrated inFIG. 2 in phantom or dotted line. In this position, the chain 24a istaut, keeping the door 12a closed. The part open position, which is notshown, is substantially the same as the intermediate position with thedoor opened approximately twice the displacement as that shown for theintermediate position. This position is substantially the same as thatfor conventional chain locks. As shown in FIG. 1, the three alternatepositions for the chain knob 26 are spaced along the horizontal to theanchor bracket 20.

Referring to FIGS. 2 and 3, the configuration of the chain knob 26 isapparent. The chain knob has a head 54 for convenient fingermanipulation, a neck 56 and an end with a first flange 58 displaced froma second flange 60. The end link 28 of the flexible chain 24 is attachedto the neck 56 of the chain knob 26 between the head and the firstflange 58. The second flange 60 is slightly smaller than the firstflange 58 to permit only the second flange 60 to be inserted in theaperture 46 in the main slot 44.Both flanges are greater in diameterthan the width of the slots in the locking plate enabling the knob totrack in the slots without jamming. In this respect, the locking plateis displaced from the door 12 by spacer plate 34 which is skeletal inconstruction, as shown in FIG. 5. The locking place 32, as shown in FIG.4, and the spacer plate, as shown in FIG. 5, have the same periphery andcoincident holes 62 for the wood screws 36.

When assembled and installed, as shown in FIG. 1, g the keyless chainlock is both efficient and convenient to operate in the manner hereindescribed.

Both plates 32 and 34 can be used for left and right side installationsby simply flipping them over individually and arranging them generallyas shown in FIG. 1.

While in the foregoing specification an embodiment of the invention hasbeen set forth in considerabledetail for purposes of making a completedisclosure.

ing plate member adapted to be secured to a door structure substantiallyadjacent said anchor member, said locking plate member having alongitudinal slot with a first end and a second end, and having furthera first curved side slot substantially normal to the longitudinal slotintersecting said slot at the first end and a sec ond curved side slotsubstantially normal to the longitudinal slot, intersecting said slotbetween said first end and said second end, said longitudinal slot beingsloped to the horizontal with said first end above said second end, saidsecond end being substantially adjacent said anchor member and saidfirst end being displaced from said anchor anchor member with saidcurved side slots each having a radius of curvature taken from a pointsubstantially at said second end and with said side slots depending fromsaid longitudinal slot when said plate member is secured to said doorstructure; and a chain member having a first end secured to said anchormem her and a second end with connecting means for engaging and trackingin said slots, said chain member being substantially taut when saidconnecting means engages said first side slot and when said connectingmeans engages said first side slot and when said anchor member and saidplate member are secured to said structures second larger flange, andsaid longitudinal slot has anaperture at the intersection of saidlongitudinal slot and said first side slot, said first flange beinginsertable into said aperture and said knob being generally movable insaid slots and retained by said plate member between said first flangeand said second flange.

3. The chain lock of claim 1 comprising further a filler bracket adaptedto be secured to said door structure immediately adjacent said anchormember and be tween said anchor member and said locking plate mem

1. A chain lock comprising: an anchor member adapted to be secured to adoor jamb structure; a locking plate member adapted to be secured to adoor structure substantially adjacent said anchor member, said lockingplate member having a longitudinal slot with a first end and a secondend, and having further a first curved side slot substantially normal tothe longitudinal slot intersecting said slot at the first end and asecond curved side slot substantially normal to the longitudinal slot,intersecting said slot between said first end and said second end, saidlongitudinal slot being sloped to the horizontal with said first endabove said second end, said second end being substantially adjacent saidanchor member and said first end being displaced from said anchor anchormember with said curved side slots each having a radius of curvaturetaken from a point substantially at said second end and with said sideslots depending from said longitudinal slot when said plate member issecured to said door structure; and a chain member having a first endsecured to said anchor member and a second end with connecting means forengaging and tracking in said slots, said chain member beingsubstantially taut when said connecting means engages said first sideslot and when said connecting means engages said first side slot andwhen said anchor member and said plate member are secured to saidstructures wherein said chain member becomes increasingly taut as saidconnecting means tracks in said first side slot.
 2. The chain lock ofclaim 1 wherein said connecting means at said second end of said chainmember comprises a knob with an end having a first flange and a secondlarger flange, and said longitudinal slot has an aperture at theintersection of said longitudinal slot and said first side slot, saidfirst flange being insertable into said aperture and said knob beinggenerally movable in said slots and retained by said plate memberbetween said first flange and said second flange.
 3. The chain lock ofclaim 1 comprising further a filler bracket adapted to be secured tosaid door structure immediately adjacent said anchor member and betweensaid anchor member and said locking plate member.